An evaluation of Panicum maximum cv. Gatton: 3. The partial digestion by sheep of organic matter, nitrogen and neutral detergent fibre of herbage at three stages of maturity during summer, autumn or winter

Abstract

The aim of this study was to quantify the partial digestion of organic matter (OM), nitrogen (N) and neutral detergent fibre (NDF) in sheep grazing Panicum maximum cv. Gatton pastures at three stages of pasture maturity during summer, autumn or winter. As pasture progressed from the young to the mature stage, OM digestibility decreased for all seasons, but OM disappearance in the rumen was unaffected. OM disappearance from the small intestine decreased with increasing pasture maturity during summer, and OM disappearance from the large intestine decreased with increasing pasture maturity during winter. N disappearance from the small intestine decreased with increasing pasture maturity during all seasons and N disappearance from the large intestine decreased with increasing pasture maturity in summer. Non ammonia nitrogen disappearance from the small intestine was decreased with increasing pasture maturity only for mature autumn pasture. Total tract N disappearance decreased with increasing pasture maturity during summer and autumn. NDF disappearance from the rumen decreased with increasing pasture maturity during autumn and winter, while NDF disappearance from the large intestine was unaffected. NDF disappearance from the total tract decreased with increasing pasture maturity during all seasons. It was concluded that P. maximum cv. Gatton pasture would best be utilized at the younger stages of development and that nutritional value would be higher in summer followed by younger autumn and winter pastures.


(South African Journal of Animal Science, 2001, 31(2): 93-100)